FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin-protein ligases (E3s). This gene encodes a member of the E2 ubiquitin-conjugating enzyme family. The encoded protein is 98% identical to the mouse counterpart. [provided by RefSeq, Jul 2008] PHENOTYPE: Mice homozygous for a knock-out allele exhibit female-specific pleiotropic reproductive defects and partial embryonic lethality at implantation. [provided by MGI curators]